service engine soon light

[dwight60]

My service engine soon light came on. I used a code reader and it said Emmissions canister and knock sensor was bad. two days later the light went out. Will the computer still retain the code even tho the light is off? and can I clear the codes by disconnecting the battery? 99 nissan pathfinder

[barnaclebob]

The code reader should be able to clear the codes. Haven't tried it with disconnecting the battery but you don't have anything to lose by trying that except radio presets...